In fixed prosthodontics, fracture of the porcelain veneer is not an uncommon problem under clinical conditions due to, e.g., malfunction, trauma or technical failures. To avoid time-consuming and cost-intensive renewal of the entire restoration, repair of the chipped veneer is desirable. The aim of this in vitro study was to evaluate the shear bond strengths of five intraoral procelain repair kits based on different chemical bonding systems. 45 metal plates veneered with feldspathic porcelain were fabricated. The surface treatment was performed using five porcelain repair systems based on tribochemical silica coating (Cojet), mechanical roughening (Silistor, Cimara, Ceramic Repair) or etching (Clearfil Repair) followed by application of silane coupling agents (five specimens each). Cylinders of composite resin of Charisma and Pertac Hybrid were bonded using Cojet, Silistor, Cimara and Ceramic Repair, and of Clearfil AP-X with Clearful Repair onto the porcelain specimens. After thermocycling (5000 cycles, 5-55 degrees C) shear bond strength was measured according to ISO 10477 followed by assessment of the failure mode. Statistical analysis was carried out with one-way ANOVA and Bonferroni-Dunn's multiple comparisons post-hoc analysis for test groups (alpha = 0.05). Shear bond strengths higher than 10 MPa were found for all test groups except for Ceramic Repair with Pertac Hybrid (8.1 +/- 1.3 MPa), which was significantly lower than all other groups (P < 0.05). Highest shear bond strength was found for Silistor with Charisma (23.1 +/- 5.8 MPa), which was significantly higher (P < 0.05) than all other groups except Cojet with Charisma (17.8 +/- 3.6 MPa) and Clearfil Repair (20.3 +/- 5.0 MPa). Cojet and Silistor with Charisma, Cimara, as well as with Clearfil mainly showed cohesive or mixed failure modes (cohesive and interfacial). Bond strengths of the combinations Silistor-Charisma, Clearfil Repair-Clearfil AP-X and Cojet-Charisma were superior to all other combinations used in the present tests.